Friday, February 8, 2019

Hit the Slopes

It's time to talk about slopes.

No, this isn't going to be a profound post about the downward slope society is in, or the slippery slopes that lead to bad habits. This is quite literally just about slopes in math. I have worked with a number of students lately who are working on this right now, so I thought maybe I would just post here and then I can tell them to refer to this blog if they have any need for review if there is anything they have forgotten.

First off, a slope is written as a fraction that tells how steep a slope is. It is written as rise over run:



So if you had a fraction, for instance, of two fifths, the slope would rise up by two for every five across. A 2/5 slope would look like this on a graph:


There are a couple more things I want to talk about here. First, you often here that a slope has to be a fraction, but they don't give you a fraction. They just give you a regular number. Well, in this case, the number is a fraction (in fact, nearly all numbers are). The number is simply over one. So if the slope is 7, that means the slope rises up seven and over one.


Lastly, let's say you have a slope that is a negative number. In this case, reading left to right (just like in a sentence), the slope will go downhill.


In this low-quality photograph, the top slope is 2/3. The bottom slope is -2/3. Left to right. If it goes up, it's positive. If it goes down, it's negative.

That's all for today. Next time, I want to talk to you about a slope that passes through a certain point on the coordinate plane.

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